The Journal of heart and lung transplantation : the official publication of the International Society for Heart Transplantation
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J. Heart Lung Transplant. · Jul 1994
Chronic counterpulsation with descending thoracic aortomyoplasty improved cardiac function in animals with heart failure.
Descending thoracic aortomyoplasty uses latissimus dorsi muscle for extraaortic diastolic counterpulsation. We hypothesized that descending thoracic aortomyoplasty could improve ventricular function in dogs (n = 5) with heart failure. The left latissimus dorsi muscle was wrapped around the descending aorta and conditioned for 4 weeks with a burst stimulator (five pulses, 33 Hz, 28 bursts/min). ⋯ Left ventricular peak pressure (98 +/- 4 to 88 +/- 3 mm Hg), left ventricular end-diastolic pressure (19 +/- 4 to 14 +/- 4 mm Hg), and stroke work (1048 +/- 124 to 743 +/- 80 mm Hg.cm3) (p < 0.05) were reduced. The end-systolic pressure volume relation increased with descending thoracic aortomyoplasty stimulation (3.7 +/- 0.7 to 4.5 +/- 0.8 mm Hg/mL), and the isovolumic diastolic relaxation time constant significantly decreased (54 +/- 6 to 49 +/- 7 msec) (p < 0.05). We conclude that descending thoracic aortomyoplasty can provide diastolic counterpulsation and reduce stroke work in animals with heart failure.(ABSTRACT TRUNCATED AT 250 WORDS)
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J. Heart Lung Transplant. · Jul 1994
Case ReportsPhysiology of the native heart and Thermo Cardiosystems left ventricular assist device complex at rest and during exercise: implications for chronic support.
Studies of patients supported with a left ventricular assist device have considered determinants of acute survival emphasizing the role of right heart function. In patients with refractory heart failure awaiting heart transplantation, chronic left ventricular assist device implantation may provide an opportunity for rehabilitation before surgery if hemodynamics are adequate at rest and during activities of daily life. For the assessment of the efficacy of the left ventricular assist device in this setting, four patients in whom the HeartMate pneumatic left ventricular assist device had been implanted were tested during graded supine bicycle exercise with Doppler echocardiography interrogation and central hemodynamic measurements. ⋯ When residual left ventricular function is sufficient, hemodynamics with exercise may be limited by peak left ventricular assist device rate. Although right ventricular function may affect acute postoperative survival, residual left ventricular function and peak left ventricular assist device rate may be important determinants of exercise performance during chronic implantation. A preliminary model of factors affecting the "left ventricular-left ventricular assist device complex" performance at rest and during exercise is presented.
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J. Heart Lung Transplant. · May 1994
Comparative StudyInhaled nitric oxide in the evaluation of heart transplant candidates with elevated pulmonary vascular resistance.
The reversibility of elevated pulmonary vascular resistance in heart transplant candidates is currently evaluated with intravenous vasodilators. The aim of this study was to evaluate the effects of increased concentrations of inhaled nitric oxide (20, 40, and 80 ppm) on central hemodynamics and right ventricular function in heart transplant candidates with elevated pulmonary vascular resistance (> 2.5 Wood units). Comparison was made with intravenous vasodilators, sodium nitroprusside, and prostacyclin in doses that lowered the mean arterial pressure by about 15%. ⋯ The pulmonary vascular resistance/systemic vascular resistance ratio, used as an index of pulmonary selectivity, was decreased by nitric oxide (p < 0.01) but not by the intravenous vasodilators. Metabolic data indicate that inhaled nitric oxide is metabolized in the same way as that formed endogenously. In conclusion, inhaled nitric oxide is a selective pulmonary vasodilator that can be used safely in the hemodynamic evaluation of heart transplant candidates with elevated pulmonary vascular resistance.
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J. Heart Lung Transplant. · May 1994
Comparative StudyFlail tricuspid leaflet after multiple biopsies following orthotopic heart transplantation: echocardiographic and hemodynamic correlation.
Flail tricuspid leaflet has been reported as a relatively uncommon complication of endomyocardial biopsy in orthotopic heart transplant recipients. However, the relationship of this complication to the number of biopsies performed and to the site of access for biopsy is not known. The objectives of this study were to assess the prevalence of flail tricuspid leaflet/torn chordae tendineae in our recent transplant population, define the relationship of this complication to endomyocardial biopsy, and to correlate echocardiographic assessments of tricuspid regurgitation severity with hemodynamic data obtained at cardiac catheterization. ⋯ The mean number of biopsies performed per patient was 15.5 (range, 2 to 27). The mean severity of tricuspid regurgitation by echocardiography was grade 3 (moderate); seven patients (33%) had severe regurgitation. The mean right atrial v wave by catheterization was 15 mm Hg (range, 6 to 26 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)